even if Demon's souls 2 was released Dark souls would feel more like Demons souls then it since it's the same devs where Demon's souls 2 would just be trying to steal the franchise back and probably not end well, I don't even see Sony doing a stupid move like that 

its sonys franchise, from is hijacking it from them, not the other way around

Sony had their chance everyone knows it, and they are the creaters, if Sony tries to use the franchise without them it won't turn out well, if Sony gets them back then thats another story, but as it stands despite Sony owning the name Demon souls, they own it's soul (no pun intended) so thats pretty much the end of that 

From Software made Demon's Souls and From Software is the Dark Souls dev.

Demon's Souls is Sony's IP but they hardly have anything to do with the development of the game. They simply made a deal with From Software most likely financing the project.

From Software created Dark Souls most likely because they wanted their next game to be multiplatform. Otherwise they would have called it Demon's Souls 2.

OT: It should do something like 2.5 million combined LT.

Actually if you keep up on the interviews and news calling it Dark Souls has nothing to do with it going multiplatform, like I said Sony had their chance but they didn't take it so another publisher moved in and offered to finnace another game (practically a sequel) and the new publishers were the ones that insisted it be made multiplatform (the devs weren't against it or anything but it wasn't their goal either) and there was actually a funny story with the name, they went through like 5 names before they settled on dark souls it seems they were trying to name it something that didn't sound like a sequel but then gave up because none of them were good 

What's Atlus' role in all of this?

None, they just published Demon's souls in NA, they have nothing to do with the "sequel"  

It will sell more obviously since it's going to be on the PS3 and XBox 360.

PS3 version alone should outsell Demon's souls , 1.4 - 1.7 M , and 700-850 for the 360 version , I hope it does more than that though .

thne game seems to have the biggest audience in americas where all of them love the box!! so im guessing it will sell better o the xbox. PS3 should have excvlusive content tho